When an ejection seat jettisons out of an airplane, it must clear the transparent canopy at the top of the cockpit. Typically, the canopy is removed before the seat is ejected. In the event the canopy is not discharged, or the plane does not have a canopy ejection system, it is desirable to have a seat capable of blasting through the canopy.
It has been found that ejection seats have difficulty penetrating the canopy with the shear force of the seat. Therefore, it is preferable to have the canopy fractured before the seat reaches the canopy. Prior attempts to fracture the canopy, include attaching a detonating cord about the canopy, to break it up when the cord is detonated. To operate, the pilot inputs a signal to a controller, that detonates the cord and ejects the seat. The seat can be catapulted either simultaneously with the detonation of the cord, or seat ejection can be delayed.
Attaching the cord to the canopy degrades canopy visibility and is a labor intensive task. Typically, the cord runs from the cockpit to the canopy, wherein the cord has a hinge point that is subject to fatigue as the canopy is repeatably opened and closed. The use of a controller also introduces an additional step and part that is susceptible to failure. Therefore what is needed is a self-actuated canopy breaker independent of a controller, that can use standard detonating cord.